** U.S.-listed shares of oil companies rise premarket after President Donald Trump imposed tariffs on Canada, Mexico and China, raising fears of supply disruption O/R

** Brent crude futures LCOc1 up 1.7% at $76.95/barrel and U.S. West Texas Intermediate crude futures CLc1 up 2.5% at $74.39/barrel

** U.S. imposes 25% tariffs on Canadian and Mexican goods, including 10% tariffs on Canadian energy imports and 10% tariff on Chinese imports from Feb. 4

** TD Cowen expects U.S. refiners that run Canadian crude on the margin to switch to light sweet crude, increasing WTI and Brent prices if tariffs go ahead

** Adds that U.S. Gulf Coast refiners will likely back out Mexican and Canadian heavy crude and make arrangements to purchase crude from other heavy sour producers such as Iraq

** "Switching will likely tighten medium and heavy sour differentials given less efficient trade flows... if it becomes too expensive to switch, refiners could run less efficient crude slates, reducing product supplied," brokerage says

** E&P cos Diamondback Energy FANG.O and Coterra Energy CTRA.N each up 1%, EQT Corp EQT.N rises 2.8% and Northern Oil and Gas NOG.N up 2.4%

(Reporting by Pooja Menon in Bengaluru)

((Pooja.Menon@thomsonreuters.com;))